Barometric switch



Sept' 4, 1956 R. w. szYPULsKl 2,761,927

BAROMETRIC SWITCH Filed Sept. 21, 1953 INVENTOR RAYMOND W. SZYPULSKI LQM RW. Ehh

ATTORNEYS United States Pa'nt BARoMETRIc SWITCH Raymond W. Szypulski, Hyattsville, Md., assignor to the United States of America as represented by the Secretary of the Navy Application September 21, 1953, Serial No. 381,523

2 Claims. (Cl. 200-83) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to barometric switches generally and more particularly to sealed pressure responsive switches for closing electrical circuits thereby to render certain control devices effective.

Heretofore, pressure responsive switches of the aforesaid type have not proven entirely satisfactory for the reason that the contact plate and contact elements often times fail to make proper electrical contact with each other as the switches were actuated to a closed position by a diiferential pressure applied thereto, whereupon the control circuits connected thereto failed to function and operate the essential control element included therein.

The present invention contemplates the provision of a new and improved hermetically sealed barometric switch device which overcomes all the objectional characteristics vheretofore encountered in prior art devices wherein means are provided for invariably and effectively closing the control circuits connected thereto as the switch is actuated in response to a minute predetermined pressure differential applied thereto. Furthermore, the present invention provides pressurev responsive devices and sealed switches void of objectional fioating and rotating contact elements and in which contact means are provided and arranged in such a manner to make and break at the same point continually during the operation of the switch. The aforesaid switch may be advantageously employed for a variety of purposes but it is particularly suitable for use with an aneroid responsive to changes in the surrounding ambient pressure and is constructed and arranged' to be actuated in response to aminute predetermined pressure differential applied thereto.

An object of the present invention is to provide anew and improved switch which is invariably and effectively actuated to a closed position in response to a minute predetermined pressure diiferential applied thereto.

Another object of the invention is the provision of a novel combination of a condition responsive device and sealed switch wherein the switch contacts make and break at the same point continually during the operation of the switch. I

Another object of the invention is the provision of a novel combination of movably open contact means adapted to render electrical control circuits eifective as the switch is closed by a pressure responsive element ,in response to a sudden change in the surrounding ambient pressure.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. l is a view partially in section and partially in ICC elevation of the barometric switch in accordance with the present invention; and

Fig. 2 is an enlarged detail sectional view of the spring loaded contact elements of the present invention.

Referring now to the drawings and more particularly to Fig. 1 thereof, the numeral 10 generally indicates the new and improved barometric switch. The switch comprises an aneroid 11 having a pair of discs 12 and 13 disposed in spaced relation with respect to each other between which is arranged an expansible bellows 14. The bellows 14 is composed of thin resilient steel or the like having one end hermetically sealed to the disc 12 as at 15, the other end thereof being hermeticallysealed to the disc 13 as at 16.

A casing generally indicated by the reference character 17 is centrally disposed within the bellows and comprises a cylindrical body 18 having a pair of flanges 19 and 21 formed thereon and extending outwardly therefrom. The casing is provided with a central well 22, the well being restricted as at 23 thereby to form a shoulder 20 the purpose of which will be hereinafter more fully described. The casing is further provided with a centrally disposed tubular member or conduit24', extending centrally from the body portion 18 thereof and threaded as at 25 for threaded engagement with an adjusting nut 26.

An expansible bellows 27 is disposed between the flange 21 and the disc 12, one end of the bellows being hermetrically sealed to the fiange 21 as at 28, the other end thereof being sealed to the disc 12 as at 29 in the centrally disposed opening 31 formed in the offset portion 32 of the disc.

A spring loaded contact unit generally indicated by the reference character 33 is arranged within the well 22 and comprises an annular member 34 composed of any material suitable for the purpose, such, for example, as iron or the like and having a fiange 35 formed thereon. The flange 35 is sealed against the shoulder and preferably secured thereto as by welding the parts together as indicated at 36. As more clearly shown on Fig. 2 the annular member 34 has arranged therein a supporting element 37 composed of suitable insulating material and having molded therein in spaced relation WithV respect to each other a pair of contact units 38. Each contact element comprises a terminal post 39 having a well 41 formed in one end thereof for slideably supporting a contact member 42. The contact member includes a shaft 43 having a disc 44 formed on one end 'thereof' and disposed within the well 41 and maintained therein' by a fiange 45 formed on member 39. The contact members are each provided with a contact 46 composed of any material suitable for the purpose such, for 'example, as platinum-iridium. The elements 42 are eachV urged outwardly by Springs 47 disposed within wells 41 and having one end in engagementiwith discs 44 and the other end thereof being in engagement With a wall formed on each of the elements 39.

The disc 13 on Fig. 1, it will be noted, has formed therewith an annular fiange 48 providing a centrally disposedl` recess 49 in the disc. Disposed within the recess and i secured to the flange 48 such, for example, as welding the parts together is a supportng member 51 having molded therein an element 52 composed of suitable insulating material such, for example, as glass or the like. Secured to the element 52 as at 53 is a contact member 54 composed of platinum iridium and adapted to engage the aforesaid contacts 46 as the switch is actuated.

In the position of the device as shown on Fig. l it Will be noted that the casing 17 is maintained in its initial adjusted position by the spring 55 and the disc 13 is maintained in its initial position by the spring 56 disposed between and` in errgagemenr with each of the discs. One endof the spring 55 is in engagement with` the-disc 13, the other end thereof being in engagement with fiange 19. Furthermore, by the aforesaid arrangement it will be understoocl` that the contact element 54 is' maintained in The switch is supportedin operationv by stud bolts 58' carried by the disc 12 and attachedZ to theV supporting member or bracket 59'by nuts-or the like 61.

By. the afo csaid disc arrangernent i- E3 and bellows arran'gement 16'-28 aV hermetica'lly sealed'chamber`62'is provided and enclosed by the aforesaid components of theswitch. The chamber is highly evacuated through a tube 63 secured' to the plate or disc 112 in any suitable manner and'in communication With the'chamber; If' desired, however, the chamber 621may be filled-'with an inert gas ofl a pressure sufiicient to compensate for the effects of temperature changes on the component partsof the switch,.andfto reduce arcing betweenv the contact surfaces andpitting'and deterioration thereof. Tube 63. isl thereafter sealed off in any suitablelmanner after the proper amount of .gas has been introduced into the Chamber 62.` Thus the aforesaid construction and arrangement inaddition to providing long dependable life forv the switch, also provides for the temperature compensation to insure uniform and dependable operation in response to a minute predetermined' pressure differenti'al applied to'the switch. Furthermore, by the use of' the pair of mutually spaced terminal posts 39 having a pair ofV spring urgedmovable elements 42 arranged therein respectively, the contact member 54 on the'disc'l'willengage the contacts 46 on the elements 42 and'invariably close the control Circuit regardless of the angle of movement of the disc 1'3 for the reason that each element 4-2' is constructed and'arranged to move independently With respect to each other. Moreover, the aforesaid arrangement provides means for establishing a' control circuit to certain control devices' in response to a relatively low contact pressure'and also provides means to allow for overtravel of thecontacts before apositive stop is reached on thefpressure switch.

From the foregoing, it will be apparent that a new and improved barometric switch has beenV devised wherein the contact elements thereof are hermetically sealed within a pressure responsive device in'such a manner to protect the contact surfaces against drt and other foreign' matter, the contact elements being constructed and arrangedito bc'moved toa closed position invariably in response to a minute precletermined pressure dilferential applied toithe switch.

Obviously many modification and variations of the present invention-are possible in the'light of the above teachings. It is therefore to be understood that within the scope of the appended claims theinventionmay be practicedotherwise than as specifically described.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A switch device comprising a pressure responsive bellows having'a movable disk sealed. in one end thereofanda hermetically sealed Chamber therein, 4a second bellows, a movable casing secured to said second bellows,

both of said bellows, disk and casing providing means for sealing said Chamber, a shoulder formed on said casing, a support composed of insulating material carried by said casing in abutting engagement with said shoulder, a pair of tub-ular elements molded in said support, a pair of yieldable contacts slideably arranged within said tubular elements respectively, a stopfo'rmed on each of said tubular elements, a complementary stop member on each of said contacts, a spring disposed within each of said tubular members in engagement with'said'complementary stop members respectively for yieldably'urging and maintaining said stop members in engagement with said stops,

a complementary contact member carried interiorly by said disk for engaging and moving said contacts independently with respect to each other in' response to a predetermined increase inl ambient pressure applied exteriorly to the first named bellows, means including a threaded tubular member formed on said casing for adjusting the initial setting of the contacts with respect to said contact member thereby to cause thev contacts to engage at said pressure, a helical spring disposed within said pressure responsive bellows and exterior to said second bellows having one end thereof in engagement with said shoulder and the other end in engagement with said disk for yieldably urging the disk to a position such that the contact member is normally disengaged from saidV contacts.

2. A switch device comprising a 'bellowsl having a movable disk sealed in one end thereof and a hermetically sealed Chamber therein, a second bellows, a hollow movable casing secured to saidsecond bellows, both of said bellows, disk and casing providing means for sealing said Chamber, a support disp'osed within and secured to said'casing, a member composed of insulatng material carried by said support, a pair of'mutually spaced tubular elements molded Within said'support, a pair of contacts, each' of said contacts being'slideably arranged'in each of said' tubular elements respectively, a stop formed on each of said' tubular elements, a complementary stop member on each of said contacts, a spring disposed' within each of said tubular members in engagement' With said complementary stop' member for yieldably urgingV said stop member in engagement with said stop, a complementary contact member carried interiorly by said disk for engaging and movingsaid contacts independently with respect' to each other in response to a pre'determinediincrease in ambient' pressure applied e'xt'eriorly to' the first named bellows, means including a threaded tubula'rimember formed on said casingfor adjusting the initial setting of the contacts with respect tocsaid complementary con'- tact member thereby'to cause the contacts to be' en'g ed' thereby at said pressure, and a helical spring disposed within said pressure responsive bellows and exterio to said second bellows having one end thereof in enggement with said casing and the other end in engagement with said disk for yieldably urging'and maintaining' the contact member in spaced relation with respect to said contacts.

References Cited in the file ofV this patent UNITED STATES PATENTS Murphy Nov; 3, 1953 Greenwood Oct: 13, 1931 

